Science Grade 9: Types of Volcanoes Quiz

Science Grade 9

• Quarter 3 - Earth and Space Module 1
• Topic: Different Types of Volcanoes

Module Information

• Curriculum: Department of Education (DepED), Philippines
• Module: CO_Q3_Science 9_Module 1
• Edition: 2020
• Intended for: Grade 9 Science students

Volcano Description

• A volcano is an opening in the Earth's mantle from which lava, volcanic ash, and gases escape.
• Magma and other volcanic materials originate from molten materials beneath the surface.
• Volcanic activity encompasses any magma movement towards or onto the Earth's surface.

Parts of a Volcano

• Summit: Highest point of the volcano.
• Slopes (or Flanks): Sides of the volcano radiating from the main vent.
• Base: Lower, outer part of the volcano.
• Magma Chamber: Region beneath the vent where magma is stored.
• Vent: Opening where magma, ash, and gases erupt.
• Crater: Funnel-shaped or bowl-shaped hollow at the top of the vent.
• Side Vent: Smaller outlet for magma escape.
• Conduit: Underground central tube or pipe connecting the magma chamber to the vent.
• Lava: Molten rock that flows onto the Earth's surface.
• Ash and Gas Cloud: Mixture of rock, minerals, glass particles, and gases released during an eruption.

Volcano Classification

• Structure: Cinder cones, shield volcanoes, and composite volcanoes.

• Activity: Based on the frequency and type of eruptions.

• Cinder Cone Volcanoes: Simplest, built from ejected lava fragments. Circular or oval cone shape with steep slopes. Most common type. Examples include Taal and Smith volcanoes in the Philippines.

• Shield Volcanoes: Broad, low-sloped volcanoes formed from fluid lava flows. Examples include Mauna Loa.

• Composite Volcanoes (or stratovolcanoes): Large, steep-sided volcanoes built from alternating layers of lava flows and pyroclastic materials. They are often more explosive than other types. Examples include Mount Mayon, Mount Fuji, and Mount Rainier.

Volcanic Eruptions

• Phreatic: Eruption due to water-magma contact. Short-lived, characterized by ash columns.
• Phreatomagmatic: Violent eruption from water-magma interaction, often producing ash and high-speed ejected materials.
• Strombolian: Periodic, weak-to-violent eruption characterized by fountain lava, like the Irazu Volcano in Costa Rica.
• Vulcanian: Tall eruption columns, often exceeding 20km, with pyroclastic flows and ash falls, like Paricutin volcano in Mexico.
• Plinian: Highly explosive eruption of gases and pyroclastic materials, extremely powerful. Examples include Mount Pinatubo.

Signs of Impending Eruptions

• Increased volcanic tremors.
• Increased steaming activity.
• Crater glow.
• Drying up of vegetation around the slopes.
• Ground swelling.
• Variation in chemical content of springs/wells.
• Development of new thermal areas.
• Changes in temperature of springs/wells/crater lakes.

Additional Notes

• The Philippine Institute of Volcanology and Seismology (PHIVOLCS) is the agency tasked with monitoring volcanoes in the Philippines.
• Volcanoes provide clues about the Earth's interior.